[1][failed verification] The rise of the party came about with a successful consummation after other attempts from various public associations, such as the Brotherhood of Tarasivtsi and the Social-Democratic Circle of Ivan Steshenko and Lesya Ukrainka, were tried.
In December 1904, the Second Congress of the RUP took place which culminated in a split with Marian Melenevsky, leading the more Marxist members to establishing the Ukrainian Social Democratic Union (Spilka) in January 1905 that later became an autonomous entity of the RSDLP and was instrumental during the Revolution of 1905 in Ukraine.
In December 1905, the RUP was renamed the Ukrainian Social Democratic Labour Party (USDLP).
Members of the party's left wing formed the Ukrainian Social Democratic Union, or the Spilka.
The USDU promoted the Russian Social Democratic platform alongside the unity of the movement throughout Russia.